It is known that silent discharge occurs when disposing a dielectric between two electrodes and applying a high alternating current voltage or a periodic pulsed voltage between the electrodes. In the resulting plasma field, active species, radicals, and ions are produced to promote reaction and decomposition of gas. This phenomenon may be utilized to remove toxic components contained in engine exhaust gas or incinerator exhaust gas.
For example, a plasma reactor which treats NOx, carbon particulate, HC, and CO contained in engine exhaust gas or incinerator exhaust gas by causing the engine exhaust gas or incinerator exhaust gas to pass through a plasma field has been disclosed (e.g. JP-A-2001-164925).